Reaction of organic substances with phosphorous sesquisulfide



Patented Oct. 4, 1949 REACTION OF ORGANIC SUBSTANCES WITH PHOSPHOROUS SESQUISULFIDE Elmer W. Brennan and Norman D. Williams, Chicago, Ill., assignors to The-Pure Oil Company, Chicago, Ill., a corporation of Ohio No Drawing. Application- December 20, 1945,

Serial No. 636,286

6 Claims. (Cl. 260-399) This invention relates to the reaction of organic substances with phosphorus sesquisulfide, andis more particularly concerned with the method of preparing additives for lubricating oils.

Lubricant additives prepared by the reaction of I phosphorus sulfides with alcohols, esters and olefinic hydrocarbons are known in the art as disclosed by patents to Loane et al., Patent 2,316,088; Smith et al., Patent 2,342,432 and Prutton, Patent 2,242,260.

An object of the invention is to provide an improved method for reacting phosphorus sesquisulfide with organic compounds and substances.

Another object of this invention is to provide an improved method for making lubricant additives by reaction of phosphorus sesquisulfide with organic compounds.

Still another object of the invention is to provide an improved method for reactingphosphorus sesquisulfide with alcohols, organic acid esters and salts, organic acids and olefinic hydrocarbons.

Still another object of the invention is to prepare improved lubricant additives by the reaction of phosphorus sesquisulfide with organic acid esters and salts, alcohols, organic acids and olefinic hydrocarbons.

Other objects of the invention will appear from the following description.

contacted with a mixture of the organic substance or compound and phosphorus sesquisulfide at elevated temperature, at such rate as to maintain the reaction mixture at the desired reaction tem perature. The reaction of the phosphorus sesquisulfide with an organic compound such as an alcohol, ester or olefinic hydrocarbon is exothermic in the presence of free oxygen. If the reaction mixture is heated to a temperature at which the reaction proceeds in the presence of oxygen the reaction mixture can be maintained at the desired reaction level by controlling the rate at 2 which air is blown through the mixture without the necessity of further heating of the mixture. Moreover, the completion of the reaction can readily be determined by drop in the reaction temperature or by failure of the temperature to increase upon increasing the rate of 'air blowing; or by the cessation of fuming. If the reaction is complete, a test sample taken from the reaction mixture and chilled down to 32 F. should leave no precipitate of phosphorus sesquisulfide when the product is examined at room temperature or, in the case of products which are solid at room temperature, when examined at their melting point. In the event the reaction mixture contains phosphorus sesquisulfide in excess of the amount which will react, the chilling test is not applicable to determine completion of the reacion.

In order to prepare oleaginous lubricant addizo tives or compositions suitable for use in the preparation of lubricant additives in accordance with our invention, an olefin, unsaturated ester, alcohol, or material containing such substances is mixed with the required amount of phosphorus sesquisulfide and heated with constant agitation to a temperature such that upon blowing air therethrough the desired reaction temperature will be maintained without further addition of extraneous heat. We have found that a temperature ofapproximately 215 to 250 F. and preferably about 240 to 250 F. will enable the temperature of the mixture to be maintained at reaction temperature by air blowing alone. The rate at which air or other oxygen-containing gas is blown through the mixture will depend upon the volume of the mixture undergoing reaction,

the nature of the organic substance undergoing reaction, the relative quantities of phosphorus sesquisulfide and other reactant present in the mixture, and the concentration of oxygen in the gas. We prefer to blow air or oxygen-containing gas through the mixture at such rate as to maintain the reaction temperature at approximately 240 to 250 F. Temperatures up to 300 F. or higher may be maintained, but it is more difficult to obtain uniform products at higher temperatures and high losses of sulfur and phosphorus result. After reaction between the organic substance and phosphorus sesquisulfide is substantially completed at temperatures not substantially above 250 F. the reaction product may be heated to temperatures up to 300 1". for a short time without injurious results. The invention is particularly applicable to the preparation of reaction products of phosphorus sesquisulfide and olefinic hydrocarbons, preferably those having at least 8 carbon atoms in the molecule, such as diisobutylene, cetene, octadecene, cerotene and melene; to the preparation of reaction products of phosphorus sesquisulfide and alcohols, both aromatic and aliphatic, preferably those having at least 8 carbon atoms in the molecule, such as octyl, cetyl, lauryl, oleyl and phenyl. octyl alcohols, and particularly those having branched chains; and to the preparation of rewas reacted with 8.8% of commercial phosphorus sesquisulfide by heating the mixture with constant agitation to approximately 230%. and then to maintain temperature of the mixture under-.

going reaction at 240 to 250 F. In this example, the total weight of reactants was 3000 grams, and the amount of air introduced into the mixture averaged approximately 45 cubic feet per hour. Profuse fuming occurred during the course of the reaction. After the phosphorus sesquisulfide was completely reacted fuming ceased and action products of phosphorus sesquisulfide and 5 the temperature dropped. Complete reaction was unsaturated salts or esters. preferably esters of obtainedinone hour. The resulting product confatty acids having at least 8 carbon atoms in tained 1.94% sulfur and 2.17% of. hosphorus the molecule such as barium and zinc oleates, by weight. The resulting product was diluted glycerol oleate and cetyl oleate; and to the prepawith 200 parts of solvent refined Mid-Continent ration of reaction products of phosphorus sesquineutral having a viscosity of 200 seconds Saybolt sulfide and unsaturated fatty acids, as for examat 100 F., and neutralized with barium hydroxide ple, olelc acid, linoleic and linolenic acids. In octahydrate at 250-260 F. with good agitation general, the invention is applicable to the various to prepare the barium salt. alcohols. esters and ,olefins disclosed in the afore- Zinc and calcium salts were prepared by mentioned patents to Loane et al.. Smith et a1. saponiflcation with zinc oxide and calcium hyand Prutton. droxide in the same manner as disclosed for As previously pointed out, instead of using pure barium hydroxide. The resulting salts had the compounds oleaginous substances containing following analyses and properties: olefins or mixtures thereof,-alcohols or mixtures thereof, or esters or mixtures thereof, may be used, as for example an olefinic polymer con- Table I taining a mixture of various olefins, a mixture of octyl alcohol isomers, or a fatty oil or wax, such as wool grease and sperm oil. Mineral on The use of air blowingduring reaction not only Salt fijgf" g g ig gw g materially shortens the reaction period, but ac- Metal) complishes a more complete reaction of the re actants, thereby minimizing the possibility of free Barium 2.82 0.10 0.64 Good. phosphorus sesquisulfidebeingiire the final iiits::::::::::::: tit 3:3 it; 53: product, and produces a product having better 40 odor and physical appearance. The use of air or other free oxygen-containing gas furthermore permit; of tt control of the reaction Blends of the three salts prepared as aforesaid Phosphorus sesquisulfld may be t g t were made with Pennsylvania neutral having a the various organic substances before mentioned Viscosity of 180 Seconds fly ol t F- s h m widely varyin u t 1 t preparation the finished blend contained 0.2% by weight of. of lubricating oil additives we prefer to use an metal. amount of phosphorus sesquisulfide equivalent W001 grease Was reacted w ph ph s t 1,5 to 12% .by weight phosphorus, based 0 sesquisulfide in the same amounts and under the th organic substance r act d th t, p same conditions just described in connection with In order to demonstrate the invention, sperm Sperm The W001 -P ph r sesqulfl having t follgwing haracteristic sulfide reaction product was also made in the conventional manner described in Example 1 ofv Saponification number 136 Patent 2,375,060. These products were saponified Acid number 0.21 with barium hydroxide octahydrate in the same Iodine number .i-'. 78.9 manner described in connection with sperm oil- Ash a Trace phosphorus sesquisulflde reaction product and solidification point O -2.0 blended with Pennsylvania neutral so that the vis. 100 F S. U. S.-- 97.2 blend contained 0.2% by weight of barium. Table Acetyl value 7.0 II shows a comparison between the wool grease- Per cent water Trace phosphorus sesquisulflde product made in the A. P. I. gravity 29.3 conventional manner, and that made with air Specific gravity 0.8800 blowing:

Table 11 Wt. Per Cent it an: 0.... ne as.

Product Product ineral Oil WithontiiirbloWing. 8hr i 1.60 2.20 Unpleasant- Poor. 'Withairblowinv 05min 1.44: 2.20 Neutral"-.- Fair.

These blends were tested in a Lauson engine and gave the following results:

the temperature at 240-250 F. for 5 hours without further addition of heat. The reaction prod- Blends of the salts of the phosphorus sequisulfide-sperm oil reaction product with a Mid- Continent SAE-lO) oil were made and subjected to the standard Chevrolet engine test. The Mid-Continent oil used was a solvent refined oil demonstrating high bearing corrosion and low engine cleanliness. Blends containing the additives in amounts equivalent to 0.2% by weight of metal present in the blend showed greatly superior results to the oil without additive, both as to bearing loss and as to engine cleanliness.

In order to further illustrate the invention a mixture of 450 grams of octylv alcohol and 50 grams of phosphorus sequisulfide were heated to refluxing temperature in a 3-neck flask equipped with a vertical condenser. After heating for several hours no reaction had taken place. The procedure was then repeated with bubbling of air through the reaction mixture at a rate of approximately cubic feet per hour. With this rate of airblowing the reaction proceeded without further addition of heat. In this work a mixture of octyl alcohol isomers was used. The resulting product (octyl phosphorus acids) can be saponified with a metallic oxide or hydroxide to give a metal salt. For example, barium hydroxide octahydrate reacts readily with the reaction products to give a barium salt which is oil soluble. Blends of the octyl alcohol-phosphorus sequisulfide reaction product with Mid-Continent solvent refined (SAE-30) lubricating oil were made and subjected to Underwood tests as described in an article entitled Automotive bearing materials and their application, by A. F. Underwood, .Journal of Society of Automotive Engineers, vol. 43, pages 385 to 392, Sep- 5 5 uct was oil soluble.

The barium, calcium and zinc salts of the resulting product can be prepared by double decomposition.

The reaction product of cetyl alcohol and phosphorus sesquisulflde (octyl thiophosphorus acids) 20 was blended with a Pennsylvania Grade (SAE-30) lubricating oil and tested in a Lauson engine. The results of the tests are tabulatedin Table V:

From the table it will be seen that the additive when present in the oil in the amount of 0.5% by weight gave the best result as to engine cleanliness, and when present in the amount of 1.5% by weight gave the best result as to bearing loss.

Blends of the cetyl alcohol-phosphorus sesquisulfide reaction product made as just described,

with Mid-Continent (SAE-30) lubricating oil, were made and the blends were subjected to the Underwood corrosion test. The results of the tests are tabulated in Table IV.

In order to further demonstrate the invention 200 grams of octadecene were reacted with 10% by weight of commercial phosphorus sesquisulfide by heating the mixture to 230 F. and then blowing air through the mixture at a rate of approximately 4 to 5 cubic feet per hour in order to As a further illustration of our invention 2000 grams of cetyl alcohol were heated with 17% of commercial phosphorus sesquisulfide to a temperature of 230 F. with good agitation. Air was then passed into the mixture at a rate of approximately 45 cubic feet per hour to maintain tember, 1938. The results are recorded in maintain the temperature at 240-250 F. without Table IV: 1 further heating for a period of 7 /2 hours, with Table IV Bearing Loss in Grams Acid No.

Wt. Per Cent P Additive 0r Additive Ou-Pb A'g-Cd inge e i n 1n Oil Viscosity After New Oil 10 hrs 5 hr. 10 hr. 5 hr. 10 hr.

Cetyl alcoh0l+l7 wt. per cent P483. 0.10 0. 0215 0.2016 0. 0017 0. 0102 48.8

Do 0.25 0.0136 0.1114 0.0041 0.0361, 34.4 3133 08 0.50 o. 0294 0. 0983 0. 0001 0. 0020 17.6 0. 31 2'50 1. 00 0. 0210 0. 0800 0. 0020 0. 0019 5.8 0.01 0' s6 0. 10 0. 0427 0. 0485 0. 0013 0. 0104 34. 5 0. 1s 1' 32 0.25 +0. 0090 +0. 0045 +0. 0037 541.0023 26.6 0.24 0.50 +0.0114 +0. 0075 +0. 0331 +0.03% 22.6 1.31 1 1s 0. 0.0050 0.0080 0.0006 0. 0008 as 0.15 0'26 0.0656 0.1485 0.7298 1.4206 350 0.09 5100 good agitation. The resulting product was a liquid'with a light yellow cast containing 4.32%

of phosphorus and 3.75% of sulfur. The resulting product was blended in the amount of 0.5% by weight with Mid-Continent solvent refined (SAE-SO) lubricating oil and evaluated in the 7 Underwood test. The results i are tabulated in Table IV. From an examination of Table IV it will be seen that the reaction product 01' cetyl alcohol, octyl alcohol and octadecene with phosphorus sesquisulfide all inhibit the bearing corrosion of the Mid-Continent solvent refined (SAE-30) lubricating oil, and that they all materially inhibit polymerization and oxidation or'the oil as shown by the per cent increase in viscosity and by acid numberafter. running the oil in the machine. The reaction product of octadecene and phosphorus sesquisulfide was outstanding both as a bearing corrosion inhibitor and in its ability to prevent increase in viscosity of the oil.

In order to determine the relative merits of products made by reacting an organic substance with phosphorus sesquisulfide with and without a temperature increase with an increase in rate air blowing, products were prepared in accordance temperature was gradually increased to 220 to 230 F. and maintained at this temperature until a satisfactory copper strip corrosion test was obtained. This required a period of six hours. The phosphorized wool grease was filtered to remove small amounts of solid impurities and upon analanalysis:

Per cent by weight Barium 2.62

Sulfur 0.41

Phosphorus 0.64

ysis the filtered'material was found to contain 1.68% sulfur and 2.3% phosphorus. One part by weight or the phosphorized wool grease was mixed with 2 parts by weight of '180 viscosity at 100 Pennsylvania neutral oil and the mixture brought to a temperature of 225 to 235 F. 0.185 part by weight of crystalline barium hydroxide Ba(OH) 2.8H2O, was slowly added with continuous agitation. A considerable amount of frothing occurred due to evolution of steam- The mixture was maintained at the aforementioned temperature until all frothing had ceased and heating was continued for approximately /2 hour thereafter to make certain that the saponification reaction had terminated. The time required for reaction of the barium hydroxide was one hour. The saponified product was filtered to remove small amounts of solid by-product materials thereby producing a homogeneous,.light brown product.

Analysis of the filtered material showed that it' ture had attained a temperature of 230 F. heating was discontinued and air was blown through the mixture at the rate of cubic feet per hour for a period of one hour. The mixture was continuously stirred during the entire time. The rate of air blowing was sufllcient to maintain the reaction mixture at 230 F. without application of heat. At the end of p the one hour blowing period the reaction was complete, as evidenced by the stoppage otiuming and the failure to obtain The theoretical The reaction mixture was then filtered at 230 F. and analyzed for sulfur and phosphorus content. It was found to have a sulfur content of 1.46% by weight and a phosphorus content of 2.23% by weight.

One part of the filtered reaction product was mixed with 2 parts by weight of Mid-Continent neutral having a Saybolt viscosityoi' 200 at F., and with barium hydroxide (Ba(0H)a.8HzO) in an amount equal to .09 part by weight of barium. The mixture was slowl heated to a temperature 01' 225 to 235 F. with continuous agitation in order to saponify the reaction product in the same manner as described in Example 1. After saponification was complete heating was continued at a temperature of approximately 340 F. for a period of 45 minutes in order to insure completion of the saponiflcation reaction and to stabilize the product. The resulting saponified product showed the following Metal salts prepared in accordance with. Examples l, 2 and 3 were tested in a Lauson engine by adding the metal salt to a Mid-Continent neutral oil having a viscosity of 180 seconds Saybolt at 100 F. in such amount that the metal content-of the oil was equivalent to 0.242% by weight of barium. The Lauson engine tests were run under the following conditions:

Jacket temperature F Sump temperature F.. 280 Load w..- 1.3 to 1.4 R. P. M 1600 Duration of tests hours 25 The results from this test showed that the barium salts of wool grease-phosphorus sesquisulfide reaction product, and sperm oil-phosphorus sesquisulfide reaction product prepared with air blowing, were as efiective as detergents and bearing corrosion inhibitors as the barium salt of the wool grease-phosphorus sesquisulfide reaction product made without air blowing. The zinc-sperm oil-phosphorus sesquisuliide reaction product made in accordance with Example 3 did not give the over-all engine cleanliness of the barium salts, but the bearings showed less corrosion with the zinc salts than with the barium salts.

It is believed that the reaction products of the various esters, alcohols and olefins with phosphorus sesquisulfide are organic thiophosphorus acids which can be esteriiied or converted into salts.

As previously mentioned, additives prepared by reacting phosphorus sesquisulfide with alcohols, unsaturated esters and olefins in the presence of free oxygen may be used per se as polyi'unctional lubricant additives. or they may be 9 converted into metal salts or esterifled and used in the form of their salts or esters.

We claim:

1. The method of reacting phosphorus sesquisulfide with an organic material reactable therewith selected from the group consisting of perature in the range from about 215 to 250 F'., and aerating said mixture with sumcient gas containing free oxygen to induce an exothermic reaction and maintain the reaction temperature within the stated range without the application of heat from an external source.

unsaturated esters of fatty acids, salts of unsaturated fatty acids, olefinic hydrocarbons, unsaturated fatty acids, and alcohols, the members of said group each containing at least about 8 carbon atoms, comprising, heating a mixture of said material and phosphorus sesquisulfide to reaction temperature in the range from 215 to 300 F., at which temperature the phosphorus sesquisulfide and the functional group in the organic material combine, and aerating the heated mixture with gas containing free oxygen at a rate which induces an exothermic reaction and maintains the mixture at reaction temperature within the approximate range from about 240 to 300 F. without the application of heat from an external source.

2. The method of preparing a sulfurizedphosphorized lubricating oil additive comprising, heating a mixture of a starting material from the group consisting of unsaturated esters of fatty acids, salts of unsaturated fatty acids, olefinic hydrocarbons, unsaturated fatty acids and alcohols, the members of said group each containing at least about 8 carbon atoms, and an amount of phosphorus sesquisulfide equivalent to about 1:5 to 12.0 per cent by weight of phosphorus based on said startingmaterial toa tem- 3. The process in accordance with claim 2 in which the organic starting material comprises, an unsaturated ester of a high molecular weight 'fatty acid and a monohydroxy alcohol.

REFEitENCES CITED The following references are of record in the file of this patent:

UNI'I'ED STATES PATENTS Number Name Date 2,133,310 Shuman Oct. 18, 1938 2,142,998 Chittick Jan. 10, 1939 2,211,231 .Henderson Aug. 13, 1940 2,308,427 Roehner et a1 Jan. 12, 1943 2,355,106 Prutton Aug. 8, 1944 2,382,121 Whittier Aug. 14, 1945 

